When cutting something a force acts on the surface, making it break into two parts. If the force is exerted on a small surface area, the force per unit surface area becomes high. Which means the pressure (pressure=,per unit surface area) increases.As the sharp side of the knife has less surface area than the blunt side, the object feels more pressure when cut from the sharp side. Therefore the cut becomes smooth.
You probably have cut bread countless times and learned never to use the flat, blunt side of the knife. You can cut smoothly only by the sharp side of it. Do you know why the sharp side cuts better?
Who found the jet propulsion mechanism? Of course, it was Mother Nature. As squids and many other animals use this, nature has the copyright!
Squids eject water while twisting it (vortex ring method). As a reaction to the force that the squid exerts on water, water exerts a force on the squid (Newton’s third law) and moves it forward. Scientists think this method would help guide capsules through the human digestive tract, enabling giving medication and diagnosis of diseases.
Did you know that when two ice cubes are pressed tightly together and then released, they fuse and become one big ice cube? Unlike most substances ice gets denser (shrinks) when becoming liquid water. So, as pressure is applied on contacting surfaces of the cubes, ice in those points tend to shrink and become liquid water (waters freezing point decreases). When the pressure is removed liquid water refreezes making the two ice cubes combine.
Did you know that CFC/Chlorofluorocarbon (found in refrigerants, air conditioners and aerosol sprays) is probably the most dangerous compound in the atmosphere? As it is an unreactive molecule, it goes up minding its own business until ultraviolet light decomposes it, producing a deadly Cl atom. This Cl atom breaks down thousands of ozone molecules heartlessly.
Did you know that mothers normally get back aches during pregnancy? As the baby grows, the mother’s center of gravity shifts forward.This creates stress on the back and leads to wrong posture as well. But,by keeping good posture back aches can be reduced.
Have you had the “umbrella turning upside down” experience during a rain? The wind drags it.But sometimes something different causes it. The air on top of the umbrella is forced to move faster than the air on the bottom because it has to travel a longer distance(because of the umbrella’s curved shape ). This causes the air on top of the umbrella to get a lower pressure than the air underneath it(As stated in Bernoulli’s law).The pressure difference creates a lift upwards and turns it upside down.
Did you know that some metals fight germs? Metals such as silver, copper, mercury, etc. and even copper alloys have self-sanitizing powers. These say goodbye to pathogens including bacteria, virus and fungi. Data suggests that silver do this by denaturing enzymes of the germs. These are especially important in hospitals and helpful to clean water.
Have you ever wondered why penguins walk funny? It is because they have short legs set far back and big feet. These are a blessing from Mother Nature for swift swimming but, not for swift walking. To lessen the inefficiency, penguins have mastered the art of waddle walking. Swaying between steps conserves momentum while raising the center of gravity and uses much less energy. Researchers think this information could help people with walking difficulties, obese people and pregnant women. Guess the new trend is “penguin” walk, forget the “cat” walk!
Summer is hot. So, the tower absorbs heat. This increases kinetic energy of the tower’s metal particles (makes them hyperactive) and weakens the intermolecular forces. So, the distance between particles increase. This makes the tower expand increasing its’ height a little. It is called thermal expansion.
Winter is cold. The tower gives away heat. The reverse effect causes the tower to shrink and get shorter. This is called thermal contraction.
The expansion and contraction cause the height difference.
Did you know that the Eiffel tower gets six inches taller in summer than winter? Can you explain why?
If we throw a ball upwards in a moving bus, it still comes back to our hands instead of falling behind. Do you know why? Well, here’s what happens;
When the bus is moving, the objects inside it also get the same velocity of the bus (otherwise the bus will leave the objects behind). So, the ball thrown upwards already has a velocity in the forward direction. The velocity in the forward direction will make it move forwards and the velocity we gave upwards makes it move upwards. Because the ball moves forwards and upwards at the same time, it will move in a curved path and then fall back to our hands.
Animals become the ultimate idols when designing robots. Now, it’s the cockroaches’ time to shine. Cockroaches have inspired scientists to build robots with their ability to squeeze and move through tiny passages. Cockroaches can squeeze up to 1/5 of their height. The new robot can run while being squashed to half its’ height. During earthquakes, landslides, etc. they will go inside the rubble as a search party, locate survivors and become heroes!
Yawning in a classroom can turn out to be a punishable offence but, did you know that yawning has a bright side too? Many thought its’ purpose was to increase the O2 level when the brain lacked O2 but, a recent study says something else. When the brain gets hot, its’ efficiency lowers. Yawning helps to cool it down.
O2 produced by plankton,sea weed,etc. and O2 from the atmosphere dissolve in water.)Moving O2(aq) to gaseous state is an energy absorbing/endothermic reaction. As Arctic/Antarctic oceans have low temperatures, O2(aq) won’t get enough energy to move to gaseous state. So, dissolved O2 tends to stay dissolved. This makes freezing cold Arctic/Antarctic oceans keep lots of oxygen. The water currents which start from there, supply O2 to other oceans as well.
Did you know that Arctic and Antarctic currents which flow to other oceans are the main oxygen suppliers to the bottom layers of those oceans? Can you explain why these cold ocean currents have lots of oxygen?
Climbing Mount Everest is undoubtedly challenging. What you are about to know will make the climb even more challenging! The bad news is, people who live in low elevations will have breathing difficulties when they visit high elevations.
This is what happens; Haemoglobin(Hb), transports oxygen to the cells as oxyheamoglobin and forms the following equilibrium.
Hb (aq) + 4O 2 (g) ⇋ Hb(O 2 )4 (aq)
As the air pressure decreases at high altitudes, O2(g) concentration decreases. According to Le Châtelier’s principle if an external impact effects an equilibrium system, it tends to counteract the effect. So, when O2(g) concentration decreases, the system tends to make more O2(g) by breaking down Hb(O 2 )4 (increasing the backward reaction rate). As a result we get less O2 to cells and suffer.
But people who live in high elevations have adapted themselves. Some have increased Hb concentration. To lessen the Hb concentration the forward reaction rate increases and gives more Hb(O 2 )4 / O2 to cells!
Do you know how submarines surface or dive? You’ll be surprised by how simple the mechanism is. It is done by controlling the density of the submarine. If the density is higher than water, the submarine dives, if it is lower than water the submarine surfaces. To change density, special tanks called ballast tanks are included. They can be filled with water or air when needed. When tanks fill with water (outside water is taken in) density of the submarine increases, when filled with air (compressed air is released) density decreases.
Bats won’t fall because they have an automatic lock system in their feet which doesn’t use energy. For this, mainly their tendons and talons come in handy. These special tendons connect talons directly to their upper bodies. Also, rough bumps like saw teeth are present on the outer side of tendons and on the inner side of tendon sheaths.
When bats relax (hanging upside down), the weight of their upper bodies pulls down on the tendons connected to the talons and they clench closed. Also, the two rows of bumps fit tightly and locks the talon joint. The mechanism is so secure that even dead bats would stay without falling!